Unitary, or one-piece lens shields for eyewear, made of optically correct, molded, plastic material have become popular in the USA and elsewhere in the world. Such lens shields are provided with a carrier which engages and holds the lens shield. The carrier has means to carry the temples.
While such non-prescription unitary lens shields eyewear are very popular for the bulk of the population there is no simple, inexpensive way for a person, who needs prescription eyewear to wear such non-prescription one-piece lens shields. Various attempts have been made, of which we are aware, such as overlying prescription lenses onto the interior surface of the existing lens shield--but this is unsightly, difficult to execute perfectly and expensive.
It is therefore an object of this invention to achieve a method and means for the manufacturer of prescription eyewear from non-prescription lens shield material in a simple and inexpensive way. Moreover, most lens shields are made from a polycarbonate or acrylic material. In molding such lens shields great care must be taken in achieving an optically correct lens shield, e.g., one without any waves or else optical distortion will result. In actual manufacturing practice, wastage of between 15% and 30% traditionally results in the making of such lens shield material. It is an object of this invention to utilize this defective lens shield material as the primary source of lens shield material, and secondarily to utilize optically correct lens shield material if defective lens material is not available.